In one embodiment, a method of forming doped regions in a substrate of a back
side contact solar cell includes the steps of depositing a first doped oxide layer
on a back side of a substrate, depositing a first undoped oxide layer over the
first doped oxide layer, diffusing a first dopant from the first doped oxide layer
into the substrate to form a first doped region in the substrate, and diffusing
a second dopant into the substrate by way of a front side of the substrate, wherein
the diffusion of the first dopant and the second dopant into the substrate are
performed in-situ. The method may further include the steps of patterning the first
doped and undoped oxide layers to expose portions of the back side of the substrate
and depositing a second doped and undoped oxide layers on the back side of the substrate.